The strongest of the forces. It is carried by the gluon and keeps quarks together in hadrons. There is also a residual strong force that is carried by mesons, keeping protons and neutrons together in the nucleus of an atom. gluon, quark, nucleus, proton, neutron, Quantum Chromodynamics, Debriefing
One of four known fundamental forces (the others are the weak force, electromagnetism and gravity). The strong force is felt only by quarks and gluons, and is responsible for binding quarks together to make hadrons. For example, two up quarks and a down quark are bound together to make a proton. The strong interaction is also responsible for holding protons and neutrons together in atomic nuclei.